Re: Measurement proposal

Neal Cardwell (cardwell@cs.washington.edu)
Sun, 17 May 1998 23:51:27 -0700 (PDT)

> > o In 3.2, we may want to use something like delta_min = 10min and
> > delta_max = 20min to provide a guarantee to our poor traceroute servers
> > that we won't ever hit them twice in the same 10min period. If we don't
> > care about this, we may want to use exponential inter-measurement times,
> > so we can enjoy the PASTA.
>
> Tom and I were discussing the various distributions that one might want to
> use in the measurements, and a pure randomization seemed more appropriate
> than an exponential distribution, at the time. Can you provide a reason
> as to why an exponential distribution would provide "better" data, than
> the uniform?

Nope. Not in any practical sense.

> > o Along with the max number of traceroutes in progress (l=60), we might
> > want to state bounds on a peak expected rate of traceroutes. Something
> > like:
> > max <= 60 traceroutes/2 secs = 30 traceroutes per second.
> > max <= T servers / 15 min <= 150/15min = 10 traceroutes/min
>
> Can you provide more detailed reasoning as to why this would be a good
> thing? I can imagine someone asking me what these values were, but I
> can't imagine why they would.

I was just thinking we might want a ballpark figure for our own purposes,
for planning wrt to disk space and nexus machine load and stuff.

> > It seems like we'd like to get a notion of paths from clients to servers,
> > and vice versa. So we could:
> >
> > To get servers:
> > o traceroute to the (say) 100 most popular web sites, as ranked by
> > excite or yahoo or whoever does that sort of thing
>
> http://www.zdnet.com/pcmag/special/web100/

Hmm. This seems to be a list of useful sites. I wonder if it makes sense
to try to find a list of popular sites instead. Of course if we got real
data on popular sites, conventional wisdom says a lot of them would be
porn sites...

neal